SQL XML路徑轉換結果錯誤

Question

其實我米begineer到SQL XML路徑，以便使我的專業，有一個場景...... 我有一個CTE功能結果

Data Chars NumberOfOccurance 
12 1 1 appears (1) times 
12 2 2 appears (1) times 
xx x x appears (2) times 

和CTE功能是：

;with cte as 
    (
     select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
     union all 
     select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from cte where startpos+1<=LEN(data) 
    ) 
    select Data,Chars,Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times' as 'NumberOfOccurance' from cte 
    group by data, chars 

其實我只想讓我的回答這個：

data Number_of_occurances 
12 1 appears (1) times 2 appears (1) times 
xx x appears (2) times 

我公頃已經嘗試這樣的：

; With Ctea as 
(
select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
    union all 
    select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from ctea where startpos+1<=LEN(data) 
) 
select Data,Chars,REPLACE((SELECT (Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times') AS [data()] FROM Ctea t2 WHERE t2.Data = t1.data FOR XML PATH('')), ' ', ' ;') As Number_of_occurances from ctea as t1 
group by t1.data, t1.Chars 

它說：

Column 'Ctea.Chars' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. 

當我使用臨時表，並讓我確切的答案，但不能做它CTE

誰能讓我的結果？

Answer 1

您可以使用FOR XML PATH這樣的級聯

;with cte as 
    (
     select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
     union all 
     select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from cte where startpos+1<=LEN(data) 
    ), CTE2 AS 
    (
    select Data,Chars,Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times' as 'NumberOfOccurance' from cte 
    group by data, chars 
    ) 
    SELECT Data,(SELECT NumberOfOccurance + ' ' FROM CTE2 c2 WHERE c2.Data = C1.Data FOR XML PATH(''),type).value('.','VARCHAR(MAX)') as Number_of_occurances 
    FROM CTE2 C1 
    GROUP BY Data 

Answer 2

的問題無關，與你的CTE。實際上，它主要表現在以下子查詢：

SELECT (Cast(Chars as varchar(1)) + 
    ' appears (' + 
    cast(COUNT(*) as varchar(5)) + 
    ') times') AS [data()] 
FROM Ctea t2 
WHERE t2.Data = t1.data 
FOR XML PATH('') 

注意你是如何在這裏使用聚合COUNT(*)以及列Chars。您需要按至少Chars這裏：

SELECT (Cast(Chars as varchar(1)) + 
    ' appears (' + 
    cast(COUNT(*) as varchar(5)) + 
    ') times') AS [data()] 
FROM Ctea t2 
WHERE t2.Data = t1.data 
GROUP BY t2.Chars 
FOR XML PATH('') 

此外，你不想t1.Chars外部查詢選擇或組，因爲它會導致每個字符數的值一行：

 
data chars Number_of_occurances 
12 1  1 appears (1) times 2 appears (1) times 
12 2  1 appears (1) times 2 appears (1) times 
xx x  x appears (2) times 

最後，你應該最有可能被使用STUFF function，而不是REPLACE，因爲你正試圖創造一個空間分隔的列表（「1出現（1）次2次出現（1）次」），而不是取代所有的空間帶有空格和分號的字符（「1;出現;（1）;次數; 2;出現;（1）;次數」）。

所以你最終的查詢應該是：

; With Ctea as 
(
    select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
    union all 
    select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from ctea 
    where startpos+1<=LEN(data) 
) 
select Data, 
    STUFF((SELECT cast(' ' as varchar(max)) + (Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times') AS [data()] 
      FROM Ctea t2 
      WHERE t2.Data = t1.data 
      GROUP BY t2.Chars 
      FOR XML PATH('')), 1, 1, '') As Number_of_occurances 
from ctea as t1 
group by t1.data